A number of compound archery bows are known which include programming means that are incorporated to regulate the draw weight of the bow such that a maximum pull weight is attained at an intermediate draw position and a reduced weight is attained at full draw.
A number of these bows, such as sold by Bear/Jennings, include cam assemblies, each having a plurality of intermediate cams in order to interconnect and synchronize the bow limbs. These bows, due to their overall complexity, require precision in assembly and manufacture and are costly.
In another known design, described in U.S. Pat. No. 5,388,564 to Islas, a compound archery bow includes a bow riser having spring power limbs cantilevered at each end. Cam pulleys are mounted on the outboard ends of each power limb and rigid limb members are affixed to the cam pulleys. The bowstring extends between the extending ends of the two rigid limb members. Endless power and reflex cables are run from the end of the riser, each cable extending along a path which passes over a cam groove of each cam pulley. An end of the cable is reeved in the cam pulley. A link member is coupled at one end to an outer point fixed with respect to the cam pulley and outer limb, and is coupled at its other end to a synchronizing pulley or wheel.
When the bowstring is drawn, the outboard ends of the outer bow limbs are pulled inwardly causing the cam pulleys to rotate due to the presence of an existing power cable. The cam pulleys wind the cable and rotate the synchronizing wheel. A rigid bar extending from the synchronizing wheel pulls the reflex cable downward and pulls the cam pulleys downwards towards the riser, in order to flex the power limbs. The power limbs then supply the energy for the flight of the arrow, and pulls the rigid limbs back to the upright position when the bowstring is released.
All current compound bows utilize some form of cam assembly to coordinate the interaction between the power limbs and the outer limbs.
Although each type of design is useful for powering arrows for flight, a need exists for a compound bow with fewer parts, lighter weight and excellent draw characteristics. Each of the above bow designs also require a considerable pull weight for use. Neither are suitable for children who do not have sufficient strength for their use. There is a further need for a bow suitable for children who want to attempt archery but are unable to do so because of size and draw weight considerations. Current art for short length draw bows for children and youth do not provide sufficient kinetic energy to satisfy the need for target penetration of flat trajectory.